Multi-user detection for Inmarsat's BGAN system

Abstract

The development and performance of a hardware-prototype multi-user detection (MUD) receiver for Inmarsat's Broadband Global Area Network (BGAN) is described. The MUD receiver is used to compensate increased adjacent channel interference due to reduced channel spacing and can simultaneously detect up to six bearers in a 200-kHz satellite subband. With this technique, the channel-spacing can be reduced from 40 kHz to 25 kHz, permitting a capacity increase of 50%. This capacity increase is achieved with an implementation loss comparable to the combined implementation loss and adjacent channel interference allowance for the non-MUD scenario. Differences between simulations and hardware implementations are discussed, as well as observed limitations on performance.